1. Field of the Invention
The present invention is directed to known sensor elements, which are used for example as exhaust gas sensors, in particular as lambda sensors, which have gained an extensive prevalence in motor vehicles. The present invention is, however, also applicable in other types of sensor elements, for example in sensors for detecting other gaseous components of exhaust gases and in particle sensors or the like. The present invention relates in particular to a sintered or sinterable ceramic sensor element which is manufactured for example by combining, in particular by stacking, individual, possibly printed, ceramic green sheets. The present invention further relates in particular to a sensor element in the interior of which a reference gas channel is formed.
2. Description of the Related Art
The sensor element of the type described above further includes in particular at least one electrical, electrochemical, and/or electronic functional element in a first end area of the sensor element generally facing the exhaust gas. An electrical supply to the sensor element is provided in the present case by a contact surface on the outer surface of the sensor element in a second area generally facing away from the exhaust gas.
An electrical supply to the sensor element is carried out in this case by an electrical connection of the functional element to the contact surface, which has a strip conductor running essentially in the longitudinal direction of the sensor element in the interior of the sensor element.
To prevent distortion due to sintering and to optimize the thermal conduction in the interior of the sensor element during operation, it is attractive to configure the strip conductor to overlap completely or partially (for example at least 10% of the width) with the reference gas channel in a top view of the sensor element. The effects in particular of the low sintering shrinkage and the low thermal conduction of a completely or partially unfilled reference gas channel may hereby be compensated for with respect to the entire sensor element.
It is problematic that, due to the aforementioned measures, an edge of the reference gas channel overlaps with the strip conductor in a top view of the sensor element, and thus in the sense of a cutting edge may potentially cause a squeezing of the strip conductor in this area during the manufacturing process.
Sensor elements of this type are known for example from German patent document DE 101 57 733 B4.